Question

You just made a cup (0.3 liters) of coffee, but it is too hot to drink. You wish to decrease the temperature of the tea from 72°C down to 64"C by submerging a numoer or aluminusp hcffefthe snd owever, instead o temperature (25°C), then how many spoons will be required to decrease the coffee to the optimum temperature? 5 spoons Assume: Cp for coffee 4184 Cp for aluminum 921 density of coffee= 1000 kg/m no heat loss from the cup mass of one entire spoon 80 grams only the submerged portion of the spoons will change temperature . onions. Estimate the A baked butter, cheese. temperature of the baked potato after preparation using the information provided below, neglecting any heat age gains or losses due heat transfer. T2 81.8°C Initial Temperature mass Cp ingredient "CF) g(oz.) 3430 2700 1260 potato 4 (39.2) 3 (37.4) 2 (35.6) 6 (42.8) 45 (1.24) 30 (0.99) 35 (1.06) 15(0.04) cheddar cheese butter sour cream (or cottage cheese) green onions 326C 3350

Answer 1

Sdleution ti Awmeunt of coffee 6ろ ll& T2 =64°C Ti 72°C 2.5°C. 4184 Spen g21 P ScotHee 30 Tams ceffee (me speen massof Veleume de00 X0.3x ニ034g Noo Heat yeauired fo be ost be coffee eu Grder to eah ahain 6yc me Cp AT 03x 4184 X (72-64 10041.6 J

+Heat gain Speens Heal est hom co ffco bne spoors nx (Heat speon tequised (Mspoan Ppn (T-25) XLetficienay nis no: Tlegieney m lo041.6 eadsads u t0041-6= 1x0.08 X 921 (If-25)xLeficieuey esuning T and since 624c the spoon i's taestug Metf- 4 hoat 3-0.75 4 nx008x921(64-25 3 4 80 100416 aue yn 6.5 5 SPOONS Aur